Air cooled cylinder for internal combustion engines



A. F. VON SVELD. JR., ET'AL 1,997,502

April 9, 1935.

. AIR COOLED CYLINDER FOR INTERNAL COMBUSTION ENGINES Filed Oct. 18, 1933 Patented Apr. 9, 1935 AIR COOLED CYLINDER FOB INTERNAL COMBUSTION ENGINES- AlexFrelherr von Seld, Jr., and Arnold Gumpreoht, Hamburg, Germany Application October 18, 1933, Serial No. 694,146

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for internal combustion engines, consisting of a number of cooling-ribs each of which is subdivided. into separate radially arranged teeth. 5 The arrangements of this kind that have become known up to now in connection with stationary air-cooling-systems with artificial air-currents, all have the disadvantage that in their case the cooling air flowing past them does not find a system of channels which are connected with one 7 another, and in which suilicient contact is established between the cooling air and the entire surface of thecooling ribs. cooling air meets with too strong a resistance Furthermore, the

interrupted in parts and which offer resistance to the flow of air within the range of these interruptions show the same disadvantages, and moreover, it is difiicult to construct them. In-

, suflicient guidance for the cooling air between the cooling ribs has the result that the cylinder receives intense cooling only on the side opposed to the flow of air, whilst the opposite side of the cylinders is left to a space which has been subjected to rarefaction of air, which means that it receives practically'as good as no flow of cooling air whatever. Owing to the manifold possibilities for the deflection oi the current of, air as for instance in the case of motorcycles such deflecting surfaces as the exhaust-pipes, the legs of the-rider etc., or in the case 01' airplanes the strong whirling of air caused by the propeller, the cooling air is not always able to flow past the cooling ribs 0! the cylinder in one and the same direction. Ii no suitable channels are provided for the air to pass through in its flowingdirection between the cooling-ribs, the air-cool ing will not be sufiicient. In so far as it is not possible in such a case to prevent the irregular cooling of the cylinder, there will be a danger of the cast-iron cylinder being distorted.

According to the invention, these disadvantages are remedied by the ,i'act that the cooling.

teeth have a rhombical cross-section and are tapered towards their free ends, the lateral suriaces oi the teeth being arranged in the direction directions to each other.

of two furrows of a screw which runin opposite Fig. 1 a cylinder oi. a combustionengine showing the newarrangement illustrative manner.

of cooling ribs, in an (01. 257-2 61) The invention concerns an air cooled cylinder Fig. 2 a part of the outer casing of the cylinder unrolled.

Fig. 3 a vertical section on line 3-3 of Fig. 2.

Fig. 4 a row of cooling ribs seen from the side.

Fig. 5 a section through one of the ribs following the line 5-5 of Fig. 4.

In Fig. 1, a represents the cylinder of a comtheir free ends. The lateral surfaces of the toothshaped cooling-ribs b are arranged in the direction oi. two furrows of a screw running in opposite directions to each other. The cylinder 0 can be constructed with its tooth-shaped cooling ribs as a metal casting in one piece. Besides, it is possible to construct the cylinder from a thickwalled hollow cylinder in such a manner that the channels provided for the flow of air passing in between the cooling ribs are milled or turnedout. For this purpose, first of all a right-handed, and then a left-handed screw-shaped groove is milled or turned into the cylinder casing. Thus, nearly trapeziform cooling-ribs with rhombical cross-section are produced. It is possible for the cooling air to flow round the cylinder, as well as to flow in a downward slanting direction through the right-handed screw-shaped groove, or in an upward slanting direction through the left-handed screw-shaped groove. The guidechannels provided in this manner for the cooling air, ensure intense cooling of the entire cylinder, the cooling eiIect bearing not only upon the part of the cylinder-wall facing the direction of the flow of air, but also upon the side of the combustion engine that lies opposite to the direction of the flow of air, without rareiaction of air being caused in this space as this is usually the case otherwise.

Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed, we declare that what we claim is:-

A cooling system, especially adapted for cylginders of combustion engines with air-cooling, consisting of a cylinder having a number of cooling-ribs radially arranged and subdivided after the manner of teeth; which have a rhombical cross-section and are tapered towards their free ends, the lateral surfaces of the teethvo'i the cooling-ribs being'arranged in the direction-oi two furrows of a screw crossing each other.

ALEX mnmnan. von snub, Jn.

ARNOLD aumnnour. 

